In recent years, large-scale integrated circuits (LSIs) for electronic devices such as mobile phones have rapidly increased their degrees of integration and numbers of layers. Thus, multipin methods for mounting an LSI on a substrate to be mounted in an electronic device have been demanded, and, for example, bare chip mounting by the tape automated bonding (TAB) method or the flip chip method is drawing attention. The former method requires highly accurate arrangement of protruding electrodes, which are connection terminals called bumps, on an LSI.
Precision components such as the bumps are produced by, for example, applying a radiosensitive resin composition to the surface of a processed product to allow formation of a resin film, patterning the resin film by photolithography, and then performing electrolytic plating or the like using the obtained resist pattern as a mask (Patent Document 1).
In cases of a radical negative-type photosensitive resin composition containing a photo-radical initiator, radicals act as active species. Thus, improvement of the pattern resolution is limited because of inhibition by oxygen contained in the air. In particular, it is known that formation of a fine pattern with a radical negative-type photosensitive resin composition causes a problem that the top of the obtained resist pattern is rounded. In order to solve this problem, a method using an oxygen inhibition layer, and the like has been proposed (Patent Documents 2 to 4).